Transcript What is a transformer?
What is a transformer?
The voltage of an alternating current can be changed using a device called a
transformer
.
A transformer contains two coils that are wound around a soft
iron core
.
iron core
The alternating current in the
primary
(
input
)
coil
produces an alternating magnetic field.
This alternating magnetic field induces an alternating current in the
secondary
(
output) coil
.
primary coil secondary coil
How does a transformer change voltage
?
The
voltage induced
in the secondary (output) coil depends on the
number of turns
on the primary and secondary coils. A
step-up transformer
has more turns on the secondary coil and so
increases voltage
.
A
step-down transformer
has fewer turns on the secondary coil and so
decreases voltage
.
Where are transformers used?
A television needs a very high voltage to operate. It contains a
step-up transformer
, which increases the voltage of the electricity supplied to the television.
This outdoor transformer decreases the voltage of the electricity carried by the national grid. It is an example of a
step-down transformer
.
How are transformers used to supply electricity?
How does electricity get to your home?